Electrical conductivity cell for measuring flow



Feb. 13, 1951 R. EGALON ET Al. 2,541,578

ELECTRICAL CONDUCTIVITY CELL FOR MEASURING FLOW Filed Oct. 2, 1947 2 Sheets-Sheet l /2 mvENroRs.

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ATTORNEYS.

Feb- 13, 1951 R. EGALON ET AL ELECTRCAL CONDUCTIVITY CELL FOR MEASURING FLOW Filed oct. 2, 1947 2 Sheets-Sheet 2 M.. r n o E M m o L E E .N 5M M v E New@ n o E 0 2 H fa Patented Feb. 13, 1951' .ELECTRICAL` CONDUCTIVITY CELL. FOR MEASURING FLOW 'Roger JirgalemV Mai-",quett-leS-Lille, Ren. Vanhille, Mouvaux, and Maurice Willemyns, Bois- Grenier, France, assignors toMa-nufactures de Produits ,Chimiquesilu Nord Etablissements Kuhlmann, Paris, France, a corporation of France Application October 2, 1ML/,Serial No; 777,434 In France June 17, 194;'7

.constituent to be absorbed by an electrolyte into which are immersed two platinized or platinum electrodes and to compare the conductivity of the electrolyte after the absorption of the gaseous component with that of the same electrolyte before the said absorption. Most usually, two electrolytic cellsfare employed, the gaseousmixture iiowing only into one of them. In each of these cells are immersed two electrodes and these two pairs of electrodes are connected to a Wheatstone bridge equipped with a galvanometer, the variations of which are graphically recorded. The two cells are placed into a common liquid in order to avoid the inuence `of the atmospheric temperature on the accuracy of the measurement.

Obviously, in order to use such a method it is necessary to provide a constant iiow of gaseous mixture and all the constituents which4 may be capa-ble of altering the measurement must first be eliminated. This may be done, for instance, by chemical transformation ofthe component to be measured to render it, alone, soluble in the absorbent electrolyte selected.

Several kinds of cells have been proposed to carry out the said method. In some of them the electrolyte flowed in a closed circuit and saturated progressively; the retained constituent was totalized without notice being given of its instantaneous Ivalue. It vneeded practice to appreciate a prohibitive content by the sole aspect of the angular coeiiicientgof ,thev obtained curve. Accordingly, such cells did not permit of an automatic acoustic `ork other signalization of a prohibitive content. In some other cells which have been proposed, the electrolyte iiows in an open circuit, but such cells are delicate and `can not be easily conveyed from any part of a shop to another. Moreover, in such cells, the thermostatic liquid generally flows outside the cell in a bulky tank` distinct from said cell.

The present invention relates to an electrolytic cell in which these drawbacks are avoided. The cell according to the invention consists of a reference-cell and a measuring-cell, both being integral parts .of a thermostatic sleeve into which they are immersed and each comprising two platinized or platinum electrodes. The reference-cell is surrounded by a coiled tubing connected at one end to the lower part of said cell and at the other to -an inlet pipe for the electrolyte. The measuring-Cenis also surrounded by r2 a lcoiled tubing connected at one end to the intermediate part ofv this latter cell and atthe .other end, to the lower part of the said cell, and `also to -the reference-cell through a 'capillary .duct which penetrates up tomid-height of said reference-cell This capillary duct is connected toa second vertical capillary duct in communication with the atmosphere. An inlet pipe forthe gaseous mixture is connected to the end of the coil surrounding the measuring-cell vadjoining the capillary duct connecting the cells, to one another, two outlet pipes. being provided in the measuringcell, one for the gas-,the other for the electrolyte. `The whole apparatus is preferably made. of .glass of low thermal expansion.

rThe electrolyteow is preferably regulated by a valve Imounted upstream with respect to the coilsurrounding the reference-cell. This valve advantageously comprises va removable .throttle havin-g several calibrated ports forming .calibrated capillaries, The spacing of the two electrodes ofthe reference-cellris. constant, but. that of the two electrodes of 1the measuring-cell is advantageously adjustable.

The electrolysis cell according to ther invention may -be used in letting the electrolyte Vflow in a closed circuit but `with thermal regeneration in this circuit.

This cell may also be used to measure with accuracy the vapour pressures. oi solutions.

Anembodiment ofthe cell according to the invention is described hereafter by way'by example with reference to the accompanying drawings in which:

Figure 1 is an elevationalview of thev cell;

Figure 2 is a side view oi the throttle of the y valve regulating the inlet flow of the electrolyte;

Figure 3 shows the'relative positions of the electrodesin the measurement-cell; and f fliigure 4 represents a particular arrangement of the cell.

As shown in the drawings the cell consists of a reference-cell I and of a measuring-.cell 2 enclosed in and sealed to a thermostatic sleeve 3. The reference-cell is surrounded by .a coil connected at one end to the lower part of cell I and at the other end toy an inlet pipe 5 for the, electrolyte. The measuring-Celli is. also vrsurrounded by a coiled tubing 6 connected at one end to cell 2 and, at the other end to cell i through al capillary tube l which penetrates up to mid-height of cell l. From the capillary tube 'l there extends another vertical capillary duct 8 in communication with the atmosphere and which terminates in a funnel opening 9. A graduated scale maybe provided on this tube to measure the amount of electrolyte owing in the capillary tube 1. An inlet tubey l0 for the gaseous mixture is connects ed at l to the end of the coiled tubing adjacent the capillary tube l. A pipe I2 connects this latter end of the coiled tubing to the lower partY coiled tubing 9 and thus assumes the same temperature of the thermostatic device. It then enters into the lower part of cell and i'llls the same up to the opening of the capillary duct 1', through which it flows, at constant level, into the flowmeter 8. At it meets the gas-escaping from pipe I9 and the ilow of which is regulated in such a way that it bubbles into the coiled tub- `ing 6. A regular chain of bubbles is thus formed in this coiled tubing as far as cell 2 in which the gas separates from the electrolyte. The used electrolyte escapes through pipe I4 and the residual gas through pipe I3. The electrolyte ow is regulated by. a valve I8 inserted in the piping 5. This valve has a removable throttle comprising a (plurality of ports |9a, |9b, |9c. 'I'he upper end of cell l is provided with a stopper 20 through which pass two conducting wires 2| extending to two platinized or platinum electrodes 22. The diameter of these electrodes is about l cm. and their height is 0.5 cm. The distance separating them in constant.

The upper end of cell 2 is also provided withA ra stopper 23 through which pass two rack-shaped tubes 24 inside which are arranged two conducting wires 25 extending respectively the two platinized or platinum electrodes 26. The racks of tube 24 engage with a pinion 27 the shaft 28 of which is fastened to two rods 29, fastened in .their turn to a collar 30 encompassing cell 2.

A knob, not shown in the drawing, is fastened to The wires 20 and 25 are connected Finally, the cell I is connected to the funnel opening 9 by a tube 3| into which is tted a three way cock 32 permitting drainage of the apparatus through tube 33.

Figure 4 represents a particular embodiment in which the electrolyte ows in a closedcircuit, by thermosyphon effect, with regeneration of the used electrolyte in this circuit. i

The outlet pipe I4 for the electrolyte is connected through a pipe 33 to a vessel 34 into which said pipe 33 extends up to mid-height above the electrolyte level. The pipe 33 passes through a sleeve 35 into which flows a heating or refrigerating liquid, entering at 35 and escaping at 31. The lower part of the vessel 313 is connected to the pipe 5 and it is provided with a drain cock l38. Provision is also made for a pipe 39 fitted with 'a stop valve 40 to admit, if desired, an inactive gas to increase the thermosyphonic motion Vand the expulsion of the desorbed gases which are expelled at 4|.

SO2 or SH2 in a gaseous mixture, using for electrovshaft 28 permitting adjustment of the spacing of .the electrodes 26 and thus adjustment of the zero .of .the scale.

to a Wheatstone bridge of known type, not shown.

lyte monoethanolamine the vapour pressure of which is negligible at C. Steam should then be admitted into the sleeve 35. If, on the other hand, the solvent is volatile at a high temperature, as is the case for distilled water, a refrigerating medium is circulated into the sleeve 35 the desorbed gases being carried along by a now of inactive gas entering at 39.

What we claim is:

1. An electrolytic cell for continuously measuring` the liow of a constituent of a gaseous mixture, comprising a thermostatic sleeve, a reference cell and a measuring cell forming integral parts of said sleeve, and contained therein and each provided with two platinized electrodes, an inlet pipe for an electrolyte, a first coiled tubing surrounding the reference cell and connected at one end to the lower part of said reference cell and at the other end to said inlet pipe, the second coiled tubing surrounding the measuring cell connected atone end to the intermediate part of said measuring cell, and at the other end to the lower part of said measuring cell, a rst capillary tube in communication with the atmosphere, a second capillary tube entering said reference cell and penetrating up to the mid-height thereof, said capillary tubes being connected to the end of the second mentioned coiled tubing adjoining the lower part of the measuring cell, an inlet tube for the gaseous mixture connected to that end of the coil surrounding the measuring cell adjoining the capillary tubes, and two outlet pipes in the measuring cell, one for the gas and the other for the electrolyte.

2. An electrolytic cell according to claim 1 in which the measuring cell is provided with a stopper, said stopper slidably carrying two rackshaped tubes each containing a conducting wire, and carrying one of said electrodes, a pinion engaging the racks of said tubes, said pinion being rotatable to adjust the spacing of said electrodes.

3. An electrolytic cell according to claim 1 in which a vessel is provided and in which a tube passing through a sleeve having inlet and outlet pipes for liquid connects the outlet pipe of the electrolyte with said vessel, said pipe extending up approximately to mid-height of said Vessel and the latter being connected at its lower part to the inlet pipe of the electrolyte to said reference cell, said vessel being provided with a pipe for the admittance of gas.

- ROGER EGALN. REN VANHILLE. MAURICE wILLEMYNs.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 933,015 Bishop Aug. 31, 1909 1,734,342 Perry Nov. 5, 1929 2,146,312 Powell et al. Feb. 7, 1939 2,329,459 Dickey Sept. 14, 1943 2,344,859 Fox Mar. 21, 1944 2,413,261 Stackhouse Dec. 24, 1946 2,462,293 Thomas Feb. 22, 1949 OTHER REFERENCES Perry, "Chemical Engineers Handbook, v2nd edition, page 868, Mixture Metering. Publ. by McGraw-Hill Book Co., New York, 1941. Y 

